Why do my subs sound bad when i close my trunk?

switch the polarity on one of the speakers and close the trunk see what happends good luck

put a dynamat trunk kit in ur ride this will stop most of the crappie noise now u will sound better coming and going down the road

Dynomat your entire car. It is not the speakers but the car that is making it sound like that. You hear a lot of rattle but dynomat will absorb some of the sound waves that cause the rattling noise coming from the car. You should be able to get enough from a local stereo shop or on ebay and let them install for you. It will greatly improve your sound on the inside and outside of the car. the bass will be clear with no rattle.

Simply put... your reverb has no where to travel besides that small trunk space. Your using speakers that were designed to reach across air molecules but isn't that the purpose of having them in such confined areas? to get that distorted thump? Myself I rather have my stuff breath and maintain a clean thump.

I have had some subs like that before too, im not 100 percent positive, but i think you need to get a different box

You need to dynomat your trunk. And also your car doors, makes it not rattle your car as much.. Dont know if thats one of the problems with the trunk though.